Ideas to keep 2 Litre SOG Bottles upright?

Has any one got a good cheap way to keep 2 litre hempys stood up? When used with 100% perlite they are liable to tip at even the slightest nudge/draft from circulation fans.

Racking my brain for a solution. Finding it hard to be creative right now.

A tight net of the right dimensions 1/3rd from the top?
A frame with them all crammed in so they cant move?
Grow stones in the bottom to weigh them down?
Crates?

Get a shallow tub large enough to fit a few plants, it can be your pot drainage tray.

Alternatively, Go to a TV store and ask if they have any tv box foam. Trace holes with a sharpy and cut with a knife. It can be your base and also keep the pots insulated at the bottom.

The same could be done on a plastic panel, plywood, depending what you have available. A 4-5” holesaw would make short work of that task.

Milk Bottle or Pop bottle crates

When I was running a 2 liter SOG army, it was in a 4x4 tray. Held 64 perlite only 2 liters. Nestled up against each other snugly they didn't move. Eh....I'm guessing you aren't running that many,so my response it moot....my bad.Milk crates worked until, I got enough 2 liters going to snug up against each other.Those rectangular shape under the bed storage bins(low profile one) @ Wally World worked out too....I used those until I got the 4x4 trays.

Get an empty tub, take the lid off, cut a hole for the 2ltr bottle, turn tub upside down, insert bottle.

Yes, this thread is very old, but I have to post because I have the perfect solution to this problem.

5 inch PVC fence posts are perfect for housing 2-liter pots and collecting the drainage. You just saw one long side off the PVC fence post and your 2-liters will fit snugly right in there. You can cut them to any lengths you would like. I have mine slightly tilted on a 2-inch slope over 8 feet, and the water drains out the end of the fence posts.

For a drain hole in the bottom end of the fence post, I just drilled a group of 1/8 inch holes so it's kind of like a screen in the PVC, so the perlite doesn't go through. I have 4 fence post (troughs, i call them) side by side, and then I have a small 2ft section of PVC fence post perpendicular to them and under them at the end that all the water drains into. From that it goes into a 1/2 inch pvc elbow to a 1/2 inch pvc line out through the wall to the bushes.